Paying the minimum on a card balance keeps the account in good standing and barely reduces the debt. The reason is in how the minimum is calculated, not in the interest rate.
The minimum is a percentage, not a payment plan
Card minimums are typically set as a small proportion of the outstanding balance, subject to a floor, plus any interest and fees charged that month.
A fixed-term loan, by contrast, is priced so that a constant payment clears the debt over a defined period. There is no equivalent design in a revolving account.
The card minimum is instead set to cover the lender's charges and reduce principal marginally, which is a different objective entirely.
The payment falls as the balance falls
Because the minimum is proportional, it declines every month as the balance declines, so the repayment slows exactly as progress is made.
This produces a curve that approaches zero rather than reaching it, and the final portion of the balance takes disproportionately long to clear.
Paying a fixed amount equal to the current minimum, rather than recalculating each month, shortens the term dramatically without feeling different at the outset.
Some issuers offer exactly this as a standing option, which converts the revolving account into something closer to a fixed-term repayment without any change to the rate.
Interest is charged on a balance that barely moves
Interest accrues on the outstanding balance, so a slow reduction means the interest charge stays high for longer.
In the early period, most of a minimum payment goes to interest and charges, with only a small remainder reducing what is owed.
The total paid over the life of the balance can therefore exceed the original amount borrowed by a wide margin, without a single missed payment.
New spending resets the arithmetic
A revolving account has no end date, and purchases added while a balance is being repaid extend it further.
Because the minimum recalculates on the new higher balance, the payment rises but the term does not shorten, so the account can persist indefinitely.
This is the mechanism by which a card intended for occasional use becomes a permanent facility carrying a balance that never quite clears.
Disclosure changed behaviour more than rates did
Several jurisdictions now require statements to show how long repayment would take at the minimum and what a larger payment would achieve.
The comparison is effective because the timescale surprises people in a way that an interest rate does not, since a rate is abstract and a number of years is not.
Requirements for these disclosures differ by jurisdiction and change over time, but where they exist they have measurably increased the proportion of holders paying above the minimum.